The present invention relates to a method for controlling a fault-state displaying means for a subscriber's card in a switching system, and in particular to a method capable of displaying a fault-state irrespective of the number of lamps for displaying the fault-state and a type of fault diagnostic function.
Usually, a switching system includes a number of boards having various functions, and a subscriber's board ( or card) also includes a number of input/output ports (I/O ports).
Since the subscriber's board has 2.sup.n (n.gtoreq.0)ports, 1, 2, 4, 8, 16, 32, 64, . . . , 2.sup.n numbers of I/O ports are contained in one subscriber's card. Also, a conventional switching system has a fault detecting function capable of detecting an operation error for the subscriber's port as above, and a plurality of lamps capable of displaying a state of fault type for each of the ports are attached thereto. For example, if the fault diagnostic function for each of the ports is of three types, a number of lamps are included to display respectively the three types of fault states for all of the number of contained ports.
Therefore, the number of lamps for displaying the fault state of the ports contained in the subscriber's board (card) is large in number, and further the structure of control logic for controlling the lamps' display is complicated. Thus, when the number of lamps mounted are as many as the number of ports on one board, a location of ports originating with a fault can be correctly displayed, however, there has been a problem that a pattern of the card becomes complicated because of an increase in the number of circuit components required additionally accompanying therewith and increasing a signal and bus for controlling the operation of the circuit components.
Therefore, when as many lamps are mounted as many as the numbers corresponding to the I/O ports are mounted, the circuit is complicated because of the increase of processing quantities, so accordingly it causes a problem that the reliability of the board decreases.